Whoa, I've had no idea that so many breweries are coming to Chicago. Even though I've read that some breweries are closing around the country, it seems that Chicago is continuing its expansion. Most of the breweries look like they are extremely local with many asking for donations to get their operations off the ground. This might suggest that people are earnest in their endeavor, but maybe don't have the financial backing; like taking a hobby and trying to make a go of it. Will this lead to a saturation of the Chicago market? Probably not. Of course, those with better brewing and business skills will survive, but I don't think any will close because of a market tipping point. Compared to other markets, Chicago still has a long way to go to catch up in terms of local breweries to population. Plus, with the decline of macro beers and the changing tastes there is a large market in the city still up for grabs. (An interesting side note is that the first rice brewery from Korea is going to setup shop in Chicago.)
What might be a trend to look for is what Last Bay Beer is doing. The people at Last Bay are trying a nanobrewery concept where they brew beer off-site and then have a small tasting room that serves growlers. This greatly reduces the brewery's footprint while allowing them to slowly expand. It's a way to start with the beer and get it directly into people's hands without the hassle of running a pub. It's probably most similar to Half Acre's approach.
Here are links to some of the new breweries. Enjoy!
https://www.facebook.com/arcadebrewery
http://4pawsbrewing.com/our-beer/
https://www.facebook.com/spitefulbrewing
http://lastbaybeer.blogspot.com/
http://www.lowdive.com/
http://broadshouldersbrewing.com/brewery/index.html
http://www.newchicagobeer.com/about/